Re: Regression due to commit 1161db6776bd1c35257e1e362e91bcb1b3fe4347 (media: usb: pwc: Don't use coherent DMA buffers for ISO transfer)

* Re: Regression due to commit 1161db6776bd1c35257e1e362e91bcb1b3fe4347 (media: usb: pwc: Don't use coherent DMA buffers for ISO transfer)
       [not found]       ` <5a5e7c14-be8a-2ad4-5ae4-7df8bcfa213e@sony.com>
@ 2020-11-23 13:32         ` Matwey V. Kornilov
  2020-11-23 13:33           ` Matwey V. Kornilov
  0 siblings, 1 reply; 2+ messages in thread
From: Matwey V. Kornilov @ 2020-11-23 13:32 UTC (permalink / raw)
  To: joro, Thimo Emmerich; +Cc: mchehab+samsung, iommu, Matwey V. Kornilov

пн, 23 нояб. 2020 г. в 14:19, Thimo Emmerich <thimo.emmerich@sony.com>:
>
> Hi,
>
> thanks for your prompt answer. Unfortunately I was out of office on Friday.
>
> Here the updates:
>   - Tracing showed the lines you mentioned.
>   - Updating the kernel to the latest stable (v5.9.10) did not change
> anything.
>   - Adding "amd_iommu=off" fixes the issue (of course including
> dysfunctional IOMMU)
>
> Best regards,
>   Thimo
>
> On 20.11.20 08:55, Matwey V. Kornilov wrote:
> > Hi,
> >
> > As far as I understand, the driver itself works correctly. It
> > communicates with the device and receives the data. Only difference is
> > that the data is zeroed. If so, it means that the memory is allocated
> > without errors and the DMA is also mapped without errors. Otherwise,
> > you would get an error when trying to open the device/start stream. To
> > finally prove this, could you please use tracing points to see what is
> > going on while the video stream is on?
> >
> > mount -ttracefs tracefs /sys/kernel/tracing
> > cd /sys/kernel/tracing
> > echo 1 > events/pwc/enable
> > echo 1 > tracing_on
> > cat trace
> >
> > And then you should see lots of lines like the following when video
> > stream is running:
> >
> > -0 [002] ..s. 34645.185239: pwc_handler_enter: dev=Philips webcam
> > 1-1.4:1.0 (fbuf=00000000303a809e filled=31581) urb=000000007e3783c4
> > (status=0 actual_length=9570)
> > -0 [002] ..s. 34645.185244: pwc_handler_exit: dev=Philips webcam
> > 1-1.4:1.0 (fbuf=00000000303a809e filled=41151) urb=000000007e3783c4
> >
> > Use
> >
> > echo 0 > tracing_on
> >
> > to disable the recording.
> >
> >
> > I've found a commit that claims to fix an issue with similar wording:
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_torvalds_linux_commit_27d2dcb1b95c8c39da417839c11eda2e665cd389&d=DwIFaQ&c=fP4tf--1dS0biCFlB0saz0I0kjO5v7-GLPtvShAo4cc&r=uorjfjHlvtqEyqWp5b8YlexJq-ujpFniwt87GU9IrXI&m=ZPgwadRZcYtXJwzoIM6ibrGC8jNcJkKloZFNKDK6PBE&s=pC6Xy7iT5Yf6nx7dSNiDOCvvCs7HENylTiquLeJ_0Og&e=
> >
> > Could you please try to boot with "amd_iommu=off" kernel command line
> > parameter and see what happens?
> > Is it also possible for you to check the latest kernel version on your setup?
> >
> >
> > чт, 19 нояб. 2020 г. в 18:49, Thimo Emmerich <thimo.emmerich@sony.com>:
> >
> >
> >> Hi,
> >>
> >> not sure about the application behaviour.
> >> I observed this green screen in MS Teams. For easy verification I used
> >> "cheese" which shows a live stream. Same behaviour.
> >> The issue is 100% reproducible: loading the stock Ubuntu (HWE) kernel
> >> module --> green screen, unloading and loading patched module --> picture.
> >> For this procedure it is even not necessary to disconnect the cam itself.
> >>
> >> I did now also another test excluding possible application magic:
> >> dd if=/dev/video0 of=/tmp/vid.raw bs=460800 count=20
> >> If I interpret this data as a video (640x720), with the patched module,
> >> I see a running sequence whereas with the stock module there are just
> >> zeros. Of course, the zeros interpreted as YCbCr stream lead to a still
> >> green image.
> >>
> >> I am using the stock Ubuntu HWE kernel (linux-image-5.4.0-53-generic),
> >> config is attached.
> >> I have to admit that I did not use the Ubuntu-patched kernel sources but
> >> the v5.4 tagged sources from git.kernel.org since I guess there are no
> >> patches in this special section. I also verified building the vanilla
> >> module has the same behaviour as the Ubuntu kernel module (green screen).
> >>
> >> I am not using the virtualization feature (currently). Nevertheless, the
> >> IOMMU is enabled (by default) in the BIOS.
> >> Unfortunately, I do not have another webcam at hand (the other ones are
> >> notebook build-ins).
> >> I checked now with another PC (ancient Intel Xeon system) - the stock
> >> driver works without trouble.
> >>
> >> Do you use/have access to a Ryzen CPU? Maybe there is some
> >> issue/specialty with its IOMMU?
> >>
> >> Best regards,
> >>    Thimo Emmerich
> >>
> >> On 19.11.20 14:26, Matwey V. Kornilov wrote:
> >>> Hi,
> >>>
> >>> I've just checked my PWC900 camera at kernel 5.9.8 and unfortunately
> >>> It works perfectly, so there issue is probably deeper.
> >>>
> >>> You say that you see the green image. Could you ensure that the green
> >>> image is what you actually get from the kernel driver, but not an
> >>> application behaviour when there are no frames.
> >>> Could you also provide your kernel build config? I see that you are
> >>> running some kind of hardware assisted virtualization, right? May I
> >>> also ask you to look for some other USB webcam (other model) around
> >>> you and check if it works at the same configuration?
> >>>
> >>>
> >>> чт, 19 нояб. 2020 г. в 14:59, Thimo Emmerich<thimo.emmerich@sony.com>:
> >>>
> >>>> Hi Matwey,
> >>>>
> >>>> I am using a Philips SPC 900NC USB webcam on my Ubuntu 18.04 system.
> >>>> Recently I upgraded from the stock kernel (4.15) to the latest HWE
> >>>> kernel (5.4).
> >>>>
> >>>> Unfortunately my camera was not working anymore. Instead a green image
> >>>> was shown and a lot of kernel messages were showing up (see below).
> >>>>
> >>>> If I revert the single commit 1161db6776bd1c35257e1e362e91bcb1b3fe4347
> >>>> from the pwc source, the camera is back.
> >>>>
> >>>> Since I guess you had a good reason to integrate this change, do you
> >>>> have any idea, how this issue could be solved?
> >>>>
> >>>> Best Regards,
> >>>>     Thimo Emmerich
> >>>>
> >>>> dmesg events:
> >>>> [Do Nov 19 10:12:50 2020] pwc: Philips SPC 900NC USB webcam detected.
> >>>> [Do Nov 19 10:12:50 2020] pwc: Registered as video0.
> >>>> [Do Nov 19 10:12:50 2020] input: PWC snapshot button as
> >>>> /devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:03:08.0/0000:06:00.1/usb1/1-6/1-6.4/input/input30
> >>>> [Do Nov 19 10:12:50 2020] usbcore: registered new interface driver
> >>>> Philips webcam
> >>>> [Do Nov 19 10:13:05 2020] amd_iommu_report_page_fault: 20055 callbacks
> >>>> suppressed
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5835e00 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5835eb0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5835f68 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5836000 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5836024 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a58360e0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5836198 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a58361c0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5836270 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] xhci_hcd 0000:06:00.1: AMD-Vi: Event logged
> >>>> [IO_PAGE_FAULT domain=0x0011 address=0x5a5836328 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] amd_iommu_report_page_fault: 20045 callbacks
> >>>> suppressed
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a58363e4 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a58364a0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a583655c flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a5838000 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a58380b0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a583816c flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a5838228 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a58382e0 flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a583839c flags=0x0020]
> >>>> [Do Nov 19 10:13:05 2020] AMD-Vi: Event logged [IO_PAGE_FAULT
> >>>> device=06:00.1 domain=0x0011 address=0x5a58383c0 flags=0x0020]
> >>>>
> >>>>
> >>>> --
> >>>> Mit freundlichen Grüßen / with kind regards
> >>>>
> >>>>      Thimo Emmerich
> >>>>
> >>>> -------------------------------------------
> >>>>
> >>>> R&D Center Europe Stuttgart Laboratory 01
> >>>>
> >>>> Phone:    +49 (0) 711 / 5858 - 282
> >>>> E-mail:thimo.emmerich@eu.sony.com
> >>>>
> >>>> Sony Europe B.V., Zweigniederlassung Deutschland
> >>>> Stuttgart Technology Center
> >>>> Hedelfinger Str. 61, 70327 Stuttgart, Germany
> >>>>
> >>>> Registered at the Court of Berlin-Charlottenburg HRB 129332 B
> >>>>
> >>>> Main Establishment: Sony Europe B.V.
> >>>> Registered Office: The Heights, Brooklands, Weybridge, Surrey, KT13 0XW, UK
> >>>> Incorporated in the Netherlands No. 71682147
> >>>> Directors: Hideyuki Furumi, Masaki Kurebayashi, Ricky Londema
> >>>>
> >> --
> >> Mit freundlichen Grüßen / with kind regards
> >>
> >>     Thimo Emmerich
> >>
> >> -------------------------------------------
> >>
> >> R&D Center Europe Stuttgart Laboratory 01
> >>
> >> Phone:    +49 (0) 711 / 5858 - 282
> >> E-mail:thimo.emmerich@eu.sony.com
> >>
> >> Sony Europe B.V., Zweigniederlassung Deutschland
> >> Stuttgart Technology Center
> >> Hedelfinger Str. 61, 70327 Stuttgart, Germany
> >>
> >> Registered at the Court of Berlin-Charlottenburg HRB 129332 B
> >>
> >> Main Establishment: Sony Europe B.V.
> >> Registered Office: The Heights, Brooklands, Weybridge, Surrey, KT13 0XW, UK
> >> Incorporated in the Netherlands No. 71682147
> >> Directors: Hideyuki Furumi, Masaki Kurebayashi, Ricky Londema
> >>
>
> --
> Mit freundlichen Grüßen / with kind regards
>
>    Thimo Emmerich
>
> -------------------------------------------
>
> R&D Center Europe Stuttgart Laboratory 01
>
> Phone:    +49 (0) 711 / 5858 - 282
> E-mail:   thimo.emmerich@eu.sony.com
>
> Sony Europe B.V., Zweigniederlassung Deutschland
> Stuttgart Technology Center
> Hedelfinger Str. 61, 70327 Stuttgart, Germany
>
> Registered at the Court of Berlin-Charlottenburg HRB 129332 B
>
> Main Establishment: Sony Europe B.V.
> Registered Office: The Heights, Brooklands, Weybridge, Surrey, KT13 0XW, UK
> Incorporated in the Netherlands No. 71682147
> Directors: Hideyuki Furumi, Masaki Kurebayashi, Ricky Londema
>
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